Metallizable benzimidazole azo dyestuffs



Patented July 5, 1949 METALLIZABLE BENZIMIDAZOLE AZO DYESTUFFS Charles E. Lewis, Somerville, N. J., assignor to American Cyanamid Company, New N. Y., a corporation of Maine York,

No Drawing. Application September 2.6, 1945, Serial No. 618,796

6 Claims. 1 This invention relates to metallizable azo dyestufis having lake-forming groups ortho to the azo group derived from fi-hydroxy-benzimidazoles. The products may be represented by the following formula:

AN=N

in which R is hydrogen or a radical of the benzene or lower aliphatic series, A is the residue of a diazotized aromatic amine having a lakeforming group in ortho-position to the azo group.

Azo dyes capable of metallization are widely used in dyeing goods, followed or accompanied by metallization treatments such as in the top chrome, bottom chrome and metachrome processes or for the preperation of complexes with salts of metals having an atomic weight from 52-64. Metallizable dyestuffs are extensively used in dying basic nitrogeneous fibers and important properties for such dyeings are high tinctorial power and resistance to fading under ultra violet light.

The dyestuffs of the present invention are of importance in all of these fields of usefulness and most of them are characterized by strong tinctorial power and superior resistance to fading.

Some typical -hydroxy-benzimidazoles which are useful in preparing the dyestuffs of the present invention arez 2-methyl-5-hydroxy benzimidazole, 2-ethyl-5-hydroxy benzimidazole, 5-hydroxy benzimidazole, 2-phenyl-5-hydroxy benzimidazole, 2-(4J-sulfophenyl) -5-hydroxy benzimidazole, 2-p-tolyl-5-hydroxy benzimidazole, 2- (4-aminophenyl) 5 hydroxy benzimidazole. These fi-hydroxy benzimidazoles are readily obtained through reduction of a 3-nitro-4-acylamino phenyl ester of an organic carboxylic acid and cyclization according to the procedure described by S. D. Gershon and G. L. Webster (J. American Chemical Society, vol. 63, page 2853, 1941).

The diazo components useful in preparing the products of the present invention are those that contain in the ortho position to the diazo group a lake-forming group which can be converted into a heavy metal complex. The lake-forming are particularly the hydroxyl group and the carboxylic acid group; also the alkoxy and halogen which under specific conditions in the process of metallization may be replaced by the complex- ,forming hydroxyl. Some typicalexamples of useful amines for the production of these diazo components are 2-amino-4-nitro phenol, 2- amino-5-nitro phenol, 3-amino-4-hydroxy benzene sulfonic acid, 2-methyl-4-amino-5-hydroxy benzene sulfonic acid, 2-nitro-4-amino5-hydroxy benzene sulfonic acid, 2-chloro-4-amino-5-hydroxy benzene sulfonic acid, 2-hydroxy-3-amino- 5-chloro benzene sulfonic acid, 3-amino-4-hydroxy-5-nitro benzene sulfonic acid, 2-hydroxy- 3-amino-5-nitro benzene sulfonic acid, 2-hydroxy-S-amino-5-su1fo-benzoic acid, 2-amino- 5-sulfobenzoic acid, anthranilic acid, 1-(4'-sulfophenyl) -3-methyl-4-amino 5 pyrazolone, 1 amino-Z-hydroxy naphthalene-'l-sulfonic acid, l-amino-Z-hydroxy-fi-nitlo naphthalene-'i-sulfonic acid, 3,3'-dichl0r0 benzidine, ortho-dianisidine and the like.

The diazo components may be also further substituted by azo groups and benzimidazoles may be used also as end components in polyazo dyes.

The invention is further illustrated by the following examples, the parts being parts by weight.

Eazample 1 \CCH| Example 2 0.05 par of the azo dyestuff obtained from Example 1 are dissolved in 300 parts of water and to the solution are added 5 parts of a 10% solution of Glaubers salt and 4 parts of a 10% solution of ammonium sulfate. 5 parts of a wettedout wool skein are added to the dye bath and the levelly dy'ed' .a .deep brown of .sornewhatabluish.

shade.

Example 3 parts of a. wetted-out wool skeln are-dyedace:v

cording to the procedure described in Example 2 and then 4 parts of a 1% solutioirziofspotassiumz;

dichromate is added to the dye batl'ii Afte'r con--- tinued boiling for 40 minutes, the wool skein is' rinsed and dried. The wool is zthus dyed.a.jet black shade of excellent fastness to lightnandm washing.

In a similar manner, .a wool dyeing is'after treated with copper sulfate solution in the presence I :of a sligh t excess 1 ofiacetici acidii producingr am-attractive violet sh ade Example. 4

Al solution oi 2196? parts. of 2 methyl =5i-ihydroxy.. benzimida'zolefin" parts. of water containing; 0.24 part of sodium'hydroxideis cooled 'by addi tion.of,ice to 5 C. and 5.4 parts ofthe'dia'zocorn pound 921 6% purity) derived" from .1 eamino-"zhydroxy naphthalene-4' sulfoni'c acid in the usual Example .5.

5 :partsi; of; "2 amino -4= nitrophenolr6esulfionici acid (93.7%.=.purity) in.6Q=aparts-of 1water COIL-n tai-ning:'loppartstofrhydrochloric acidal7 are? diazotizedxby, the;additions.of.--20--partseof a'.-!7.%,=- sodium nitrite solution .The, diazo; solutioni so obtained is added to,a stirred. solution containing 2.96 parts of 2-methyl'-'5'-'hydroxy benzimidazole, 5 partsof .20 %:;sodiuma hydroxideisolutionr:and 20.:parts of.105%:sodium:carbpnatesolutiom int10.0..-

parts; ofa water; The temperature is1-..ma,intain*ed-2 at1-5f. 0.1.during; the, addition and while=stirring-to b completion of the; coupling-. 'I'herdyestufdisfpne.-=-

cipitated byaacidifxin cthe.solutiomwith :hydm

* of water.

4 chloric acid to an acidic test to Congo red paper followed by addition of salt, and is separated by filtration.

This dyestufi produces on wool a yellowish brown according to the dyeing procedure of EX- ample' 2...

1.89%parts of-2'-aminophenol-4-sulfonic acid in 35"part-s of water is treated with 1.25 parts of hydIOGhlOIiOizflCid (1.19) and is diazotized by the addition of 10 parts of a 7% solution of sodium nitrite... The-,- .diazo. solution as.obtaine.d .is added slowly. .to can. agitatedlsolution. containing ,1.48.. parts .-.of.'. 2-Imethyl-5f-hydr'oxy; benzimidazole, 5.: parts. of 20%. sodium hydroxide .solutiorn and.=20;. parts of 10 %sodium carbonate solutioninfimpartse.

The reaction mixture is maintained at 5 C. during this addition\and until completion of the coupling. 'After acidification with hydrochloric acid to*an:acidic test against Congo red test paper, the product is\pr.ecipitated by addition of salt and is separated by filtration.

The idyestuffi: so-.:obtainede dyes awool l'iaccondihg i to;.the:::=proced11re-;.describedtiniE xampleaz a yel. lowisli brown'rsha-dem This econvertedaby the e 1.83;.zparts1saof: 2 amino4+nitrophenoln (8.4% pmty) imflil-spantsiofi.watereare treatednwitm parts;ofrhydrochloniceacidri17%? .andathem wi 10 partsaof: 9,1 1 :%.s'solutiomcfrsodinmmitrite;.r The? resultin adiazoi sclutiemise addedsatalomtemweratureto, .an'sa itatecb solutiom containing l'rlfiinartszs of;,2methyl 5 hydroxy benzimidaaolea;zrpantss or a 20 L solution of) so.dium-.-hydroxiderand-eparts; ofi-a.--;10.%;..solutiOmof sodiumncarbonatevim 50;\par tst ofi water-1.v Wham-.couplingis complete the dyestufi isseparated.by iiltration. r

The. -dyestufi; so.. obtained dyes =woo1eaccording to. the :procedure described in Example; 2,.zarred-: brown sha de.,., is com/7erted,bythetopchromee procedure. to, a chocolate. brown .and...by.,after,. treatment with coppensalt. to .a reddish tan; shade;

The term Flake-forming group,'is" used in the. specification and' claims inits" ordinary meaning. inthe chemistry -of metalliz'ableazo dy'es namelyfg a group which is capable of forming a complex with metals--havingarn atomic weight from 52 364, I such groups being normally-hydroxylf alkbxy-," chlorineand carboxylic -acid groups:

The term lower alk yl isaused in its ordinary sense: as covering alkyl groups having 'from 1=5 carbon'ato'm'sa 1 I- .claim :5

. 1. eA=-:metalliZa-ble:azmdyestuffi ipnezpared bymodplinge, asdiazotizedlztcarhonyclic varomatic's. amine:

havingitnotamorecthan ctwoacnucleiaandrhavingaga lake-forming group ortho to the diazo group with a. compound of the formula.

HO@N\G R in which R is a member of the group consisting of hydrogen, mononuclear aryl, and lower alkyl.

2. A metallizable dyestufi according to claim 1 in which the substituent on the 2-carbon atom is lower alkyl.

3. A metallizable dyestuff according to claim 1 in which R is methyl.

4. The metallizable azo dyestuff obtained by coupling diazotized l-amino-G-nitro 2 napththo1-4-sulfonic acid with 2-methy1-5-hydroxybenzimidazole.

5. The metaliizable azo dyestufl obtained by coupling diazotized Z-amino 4 nitrophenol-fisulfonic acid with 2-methy1-5-hydroxybenzimidazole.

6. The metallizable azo dyestufi obtained by coupling diazotized 2-amino-4-nitrophenol with Z-methyl-5-hydroxybenzimidazo1e.

CHARLES E. LEWIS.

REFERENCES CITED UNITED STATES PATENTS Number Name Date 1,241,153 Schlile Sept. 25, 1917 1,292,385 Anderwert et a1. Jan. 21, 1919 1,972,988 Giemsa. et a1 Sept. 11, 1934 2,109,552 Schindhelm et a1. Mar. 1, 1938 2,203,196 Hanhart June 4, 1940 2,270,451 Keller Jan. 20, 1942 2,282,323 Dickey et a1 May 12, 1942 2,308,023 Peterson Jan, 12, 1943 FOREIGN PATENTS Number Country Date 353,273 France L June 24, 1905 181,783 Germany Mar. 1, 1907 458,843 Great Britain Dec. 28, 19.36 491,551 Great Britain Sept. 5, 1938 

